Well-boring tool.



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' wm omNG Toon. APPLICATION EILED EEB. 29.1916.

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MZAWnl-MWl//yf//w I l -V STEVEN TOTH, OF LOS ANGELES, CALIFORNIA;

WELL-:BORING Toot.

specification or Letters Patent.

Patented Mar. T2, T918.

Application filed February 29, 1916. Serial No. 81,147.

To all whom t may concern.'

Be it known that I, STEVEN TOTH, a citizen of the United States, residing at Los Angeles, in the county of Los Angeles and State of California, have invented new and useful Improvements in Well-Boring Tools, of which the following is a specification.

This invention relates to well boring tools and pertains especially to drills. In the ordinary methods of drilling wells a rotary drill is employed to drill the well hole in advance of the well casing. The latter is lowcred into the bore following the drill as it progresses in the boring operation. It is necessary to bore the well hole of the diameterI not less than the outside diameter of the casing in order that the latter may follow the drill. To accomplish thisit is necessary to have the jaws of the drill spread a distance not less than the outside diameter of the casing.

Frequent resharpening of the jaws of the drill is required necessitating the removal of the drill. The drill stem extends to the surface of the ground through the well casing, and if it is desired to remove the drill from the bore the casing must be removed which is an expensive operation and consumes a great deal of time and labor. In order to overcome this objection drills of the underreamer type have been provided having jaws which may be expanded to a spread greater than the outside of the casing and contracted to a spread less than the inside diameter of the well casing.

The objects of my invention, are, first, to provide a drill having expansible jaws; second` to provide means for expanding the jaws which operates automatically on the drill being positioned for boring; third, to provide means for retracting the jaws which operates automatically, the drill being raised from its boring position; -and fourth, to provide a drill with means for preventing too rapid cutting.

I have illustrated an embodiment of my invention in the accompanying drawing, in which:

Figure 1 is a vertical section of a well bore and casing with my improved drill shown Ain elevation and in boring position.

Fig. 2 is a view similar to Fig. 1 showing the drill in position within the casing.

Fig. 3 is a view looking upward at the bottom of the drill. i

Fig. 4 is a vertical section as seen on the line 4-4 of Fig. 3.

Fig. 5 is a section as seen on the line 5 5 of Fig. 3.

Fig. 6 is a horizontal section as seen on the line 6-6 of Fig. 1.

Referring more particularly to the drawing, 7 indicates the bore of a well hole within which is disposed the usual well casing 8 in position to be lowered as the drill advances in its boring operation. My improved drill is indicated at 9 and is shown in Fig. l with the jaws resting upon the lower part of the bore in position for drilling. In Fig. 2 the drill is shown in position to be lowered for further boring, or in position while being raised for removal of the drill. The usual hollow drill stem is indicated at 10 and is connected to the drill, later described.

The drill comprises a stock or shank 11 which is of cylindrical form at the upper end .and flares outwardly toward the lower end as indicated at 12. Adjacent the lower end is an inwardly tapering portion 13. The specific shape of the drill shank is not a feature of my invention except that it should be provided with a lower surface 14 which serve's'as an abutment for the drill to rest upon the material at the bottom of the bore in case the drill cuts too rapidly an-d the jaws sink into the material through which the boring operation is being performed. The upper end of the shank is provided with a stem 15 which is threaded to engage threads on the inside of the drill steml section 10.

A bifurcated bore extends through the shank, twoarms thereof 16 and 17 joining into a common duct 18 which extends through the stem and connects to the ybore of the drill stem section 10. The ducts 16 and 17 open at their lower ends as indicated at 19 and 20. and are for the purpose of feeding water to assist in the drilling operation. Water is fed through the hollow drill stem sections, passes through thev duct 18 emerging from the drill shank through the ducts 16. and 17.

Formed in the drill shank 11 are grooves 21 and 22 which extend axially of the shank and substantially radially. Each of the grooves 21 and 22 are provided with walls 23 and 24 respectively against which the jaws of the drill are adapted to abut and are open at the lower ends through the surface 14. The slots 21 and 22 form ways,

the inner of the bottom walls thereof being oblique to the axis of the shank as indicated by 25 and 26. The bottom of the slots 21 and 22 are enlarged as indicated at 27 and 28, thereby forming abutments.

Disposed within the slots 21 and 22 are jaws 29 and 30. These jaws have dimensions conforming to the dimensions of the slots 21 and 22 with enlarged portions at the inner end to' coperate with Athe abutments 27 and 28 and prevent displacement laterally of the jaws. The obliquely arranged bottom walls 25 and 26 of the ways provide guide means so that when the jaws are in their lower positions shown in dotted lines in Fig. 4 and in full lines in Fig. 2, they will have contracted and have a spread not greater than the inside diameter of the well casing for which they are designed. When the jaws are in their upper position abutting the walls 23 and 24 of the ways, the jaws will be spread as shown in full lines in Figs. 1 and 4.

In order to prevent the jaws from being displaced from the shank when the drill is being raised or lowered, I have provided slots 31 and 32 disposed parallel to the inner surface of the jaws. Screws 33 and 34 extend through the walls-of the ways and are disposed within the slots 31 and 32. The heads of the screws being counter-sunk so that they will not form an obstruction on the surface of the shank: These screws form limiting devices to preventlongitudinal displacement of the jaws, as the jaws move downward until the pins abut the upper end of the slots 31 and 32. When the drill is lowered into the casing the weight of the jaws 29 and 30 will cause the latter to move downwardly until the ends of the slots 31 and 32 abut pins 33 and 34. In this position the jaws have moved inwardly with their inner ends preferably overlapping a slight amount, and with. a spread equal to or less than the inside diameter of the well casing 9.

When the drill reaches the bottom of the bore the jaws rest upon the surface of the bottom and are forced upwardly into the shank, thereby moving the jaws outwardly and expanding them to a position shown in and 34 have abutted the ends of the slots 31 and 32. If they are hindered from moving downward by their own weight then as the drill is lifted the jaws will engage the lower part of the basing 8 and will be moved downwardly,` and inwardly by reason of the casing abutting them.

The spread of the jaws of the drill may bel varied by changing the inclination of the bottom of the ways 21 and 33 for any particular drill. A drill may be designed to produce a spread sufficient for the particular character of material being drilled, and the size of the well casing.

What I claim is: 1. In a well boring tool, the combination of a stock provided with independent or non-communicating slots in its outer wall which are enlarged at the inner or bottom portions and having bottom walls oblique to the axis of the said stock, jaws disposed for free 'sliding movement in said slots to expand or contract therein, each jaw having an enlargement disposed in the enlarged portions of said slots for preventing displacement of said jaws radially, and independent means for each jaw to limit axial movement of the same.

2. In a well boring tool, the combination of a non-bifurcated stock provided with longitudinally extending slots separated by a central core extending to the bottom end of the stock and having oblique walls forming thel bottoms of the slots, jaws slidably disposed for free longitudinal movement in said slots to expand or contract in the same, slots extending through the jaws, and a pin for each jaw disposed in said stock and extending across the slots in said stock and through the slots in the jaws for limiting sliding movement thereof axially.

In witness that I claim the foregoing I have hereunto subscribed my name this 16th day of February, 1916.

STEVEN TOTH. 

